Business Source License 1.1
Source code is visible but you cannot use it commercially as a competing service. Converts to open source after a set date.
Commercial use
✗ No
Modify
✓ Yes
Distribute
✗ No
Must open source changes
✗ No
Must attribute
✓ Yes
Patent grant
✗ No
What this license means
BSL is a 'source-available' license used by companies like HashiCorp, MariaDB, and Sentry. You can read and modify the code, but you cannot offer it as a commercial service that competes with the original. After a change date (typically 3-4 years), the code automatically converts to a truly open source license (usually Apache 2.0).
When you encounter this license
Read the Additional Use Grant carefully — it defines exactly what's restricted. Using BSL tools internally is usually fine. Running them as a competing hosted service is not. Each BSL license has specific terms about what constitutes 'competing.'
Watch out for
This is NOT open source by the OSI definition. The source is available to read, but the usage restrictions make it source-available, not open source. Some developers feel strongly about this distinction.
This guide is for informational purposes only and does not constitute legal advice. For licensing decisions in commercial products, consult a qualified attorney.